Newest Admob unity play-services not found

Hello guys! I have a small issue on unity admob that is driving me insane . I have been trying since last month to update sdk and jdk and ndk and different versions and the android resolve is always failing with this error message Missing Android component com.google.android.gms:play-services-ads:18.3.0 (Android SDK Packages: )
Does anyone know why I am getting this no matter what I do?

I finally found the solution to my problem. For people who has the same problem this is what I did:
1- uninstalled unity and unity hub
2- went to unity download archives and installed latest stable unity version (2019.2.18f1 in my case) without the use of unity hub and made sure to tick the android checkbox in the download
3- got the latest admob plugin from google
4- selected a higher target api (android 9 in this case)
5- the resolution was successful